LONDON — British police declared at least two major incidents Saturday night after multiple people were reported to have been injured when a van veered into pedestrians on London Bridge. There were later reported stabbings in a nearby market.

Witnesses reported that a white van was traveling fast — approximately 50 miles per hour — when it mounted the sidewalk and plowed into a group of people crossing the Thames River on foot.

Police said there had been at least one fatality. Holly Jones, a BBC reporter who was on the bridge at the time, said five people were being treated for injuries. The news service reported that police were seeking three suspects in connection with the incident.

Police later confirmed a second incident at Borough Market, an area packed with popular restaurants that is located just south of the bridge. Police said that armed officers were responding to the scene, and that there were reports of injuries from a knife attack.

Police said shots had been fired at Borough Market. Cell phone video from a restaurant in the market showed people diving under tables amid the sound of breaking glass as officers rushed in and ordered patrons to stay down.

London’s Metropolitan Police said they were responding to a third potential incident in the Vauxhall area, which is about a mile from the scene of the first two incidents. The subway station at Vauxhall was briefly closed, but later reopened.

Dozens of police cars sped to the scene of all three incidents, with helicopters hovering overhead. Police closed London Bridge and urged the public to avoid the area.

Witnesses reported hearing gunshots at the bridge around 10:30 p.m.

“I heard many gunshots and I heard people running away,” said Joe Dillon, 23, who was near London Bridge when the incident occurred. “Police officers were shouting: ‘Get out of here, you need to go!’ I heard at least eight rounds of gunshots, but I’m not sure who was shooting. When I arrived a second after I had heard the screams and the shots, I saw five or six officers running toward the van.”

The incident caused chaos in the heart of London in an area normally bustling on a Saturday night. Pedestrians near the bridge said they were ordered by police to run. Video footage showed people fleeing in a panic. Two hours after the incidents began, police were still widening cordons and pushing bystanders further back from the scenes.

The office of Prime Minister Theresa May said she was returning to Downing Street and was being briefed by security officials.

President Trump was briefed on the incident, and immediately took to Twitter to say: “We need to be smart, vigilant and tough. We need the courts to give us back our rights. We need the Travel Ban as an extra level of safety!”

In a follow up tweet minutes later, he wrote: “Whatever the United States can do to help out in London and the U. K., we will be there – WE ARE WITH YOU. GOD BLESS!”

Saturday’s incident comes less than two weeks after 22 people were killed in a bomb blast following a Manchester concert. And it comes less than three months after a driver killed four pedestrians on another Thames crossing, Westminster Bridge. The assailant then stabbed to death a London police officer at the gates of Parliament.